Hi Lukasz,
that should be possible, but I would connect from a server to the switch, because the manual states that:
Only password-based authentication is supported for SSH/SCP client.
You can put SSH keys on the switch and use public key based authentication with SSH/SCP for accessing the switch.
You should at least restrict access to just your Amazon server, not allow all Amazon servers (or everybody) access to the switch, but it would be better to use local server for communicating with the switch.
I would suggest to use a local server to collect backups from the switches, and then securely copy them from the local server to the cloud server, without allowing access to the local server from the cloud server (e.g. using a stateful firewall).
Thanks,
Erik